import type http from 'node:http';

export function sendJson(res: http.ServerResponse, statusCode: number, payload: unknown) {
  res.statusCode = statusCode;
  res.setHeader('Content-Type', 'application/json; charset=utf-8');
  res.end(JSON.stringify(payload));
}

export function isCallbackAuthorized(req: http.IncomingMessage, authToken: string) {
  if (!authToken) {
    return true;
  }

  const headerToken = req.headers['x-callback-token'];
  const authHeader = req.headers.authorization;
  const bearerToken =
    typeof authHeader === 'string' && authHeader.startsWith('Bearer ') ? authHeader.slice('Bearer '.length) : null;

  return headerToken === authToken || bearerToken === authToken;
}

export function readRequestBody(req: http.IncomingMessage, maxBytes: number) {
  return new Promise<string>((resolve, reject) => {
    const chunks: Buffer[] = [];
    let total = 0;

    req.on('data', (chunk: Buffer) => {
      total += chunk.length;
      if (total > maxBytes) {
        reject(new Error(`Payload too large (>${maxBytes} bytes)`));
        req.destroy();
        return;
      }

      chunks.push(chunk);
    });

    req.on('end', () => {
      resolve(Buffer.concat(chunks).toString('utf8'));
    });

    req.on('error', (error: Error) => {
      reject(error);
    });
  });
}